Consumer electronic products being equipped with a wired remote control are known from the prior art. Especially for portable consumer electronic products such as CD players, cassette players, MP3 players, etc. these wired remote controls are used frequently. For these audio devices, as listed above, some headphones belong to the first priority peripheral equipment of these devices. An advantageous solution is to combine the headphones with the wired remote control so that only one single cable is necessary for connecting the headphones and the wired remote control to the portable device.
Recently, the wired remote controls have taken over the additional function of informing the user about operation modes, recorded titles, and any kind of user information by means of the implementation of a small display in the wired remote control. The display can be of any type but at present usually an LCD display is used for this purpose. In this case, the display data can either be generated in the wired remote control itself or the data can be transferred from the portable device to the wired remote control in another embodiment. The first alternative requires a relatively expensive memory device for the display data in the wired remote control and also some more powerful micro-controller for the generation of the data signals evaluating user controls etc. The required remote control should of course be light weighted, and small sized so that the first embodiment is more difficult to achieve under these constraints. That is why the second alternative solution is preferred, mostly. But in that case all LCD display data needs to be transferred to the wired remote control from the portable device and this calls for an effective communication system and communication method between the portable device and the wired remote control. Also the number of wires necessary for the communication shall be as small as possible in order to assure the lightest weight cable connection and the best protection against electromagnetic interferences.
Under these constraints a serial bus communication is considered best to fulfill the requirements.